Once the CO2 has been captured it may be used as a raw material. But at present the volume of CO2 liable to be captured is several orders of magnitude greater than the market for CO2 uses, so such uses are regarded as a solution complementary to storage.
Carbon dioxide is an industrial gas with a large number of applications including the manufacture of chemical products or use in cooling systems, welding systems, fire-fighting, the food and paper industries or horticulture and many other small-scale applications.
Large volumes of CO2 are also used in oil fields to increase the amount of crude oil extracted (especially in the US) using the EOR (Enhanced Oil Recovery) technique.
A number of novel CO2 applications are also emerging in which the gas is used as a carbon source in synthesising polymers and various chemical products.
Another potential application would be the production of carbon-based fuels (chiefly methanol). Briefly this would involve obtaining hydrogen from renewable or nuclear energy and using CO2 to make a fuel suited to the current techno-economic situation as a bridge to the so-called “hydrogen economy”.
Finally research is being done on capturing CO2 in the form of biomass using various organisms such as microalgae.